Soak the dried shrimps in warm water for 10 minutes. Drain the water and chopped the dried shrimps into small pieces. Steam the tofu for 5 minutes and set aside. Heat up a wok with some oil and stir fry the dried shrimps until fragant. Add in the water, oyster sauce, soy sauce and bring it to boil. Add in the scallions, red chili, sesame oil, salt and sugar (to taste) and white pepper powder. Quick stir for 30 seconds and pour the toppings onto the steamed tofu. Serve hot with rice.